Pressure-control system



Feb. 26, 1929 1,703,455

T. A. PEEBLES PRESSURE CONTROL SYSTEM Filed Sept. 5, 1925 the new boilers.

Patented Feb. 26, 1929.

THOMAS .A.. PEEBLES, OF PITTSBURGH, PENNSYLVANIA.

PRESSURE-CONTROL SYSTEM.

Application filed September 3, 1925.

This invention relates to the use of fluid pressure and more particularly to a control system for fiuid pressure lines such, for example, as the steam pressure lines in general use.

Due to the increased economy in the operation or high pressure steam turbines and engines over those operated at low pressures, it is now customary in installing new boilers, to put in those which operate at a materially higher pressure than that which the old boilers operate, and steam consuming units designed to w rlr at the higher pressure are likewise installed for use in connectionwith As a result many plants must maintain two systems working at different pressure when in operation.

Due to the improved design of the new, high pressure boilers and the better means for securing complete combustion, the new boilers are always more economical than the old low pressure boilers. For the most economical operation of such a plant it is, therefore, desirable that the greatest possible amount of steam pressure for-both the high and low pressure systems be supplied from the high pressure boilers, thereby reducing the amount of coal which must be burned under the less eiiicient low pressure boilers.

An object of this invention is to provide .a control system for delivering pressure from a high to a low pressure system in accordance with the demand upon. the latter, but wherein such supply is reduced in accordance with a predetermined drop in the pressure ofthe high pressure system so as to prevent drain age by the low pressure system should the demand upon the latter be greater than the high pressure system can meet in addition to the requirements of the high pressure steamconsuining units.

A further object'is to provide a system for delivering fluid pressure to a low from a high pressure system of such arrangement that t-he high nessurc system will be safeguarded against the low pressure system becoming a drain upon it so that a decrease in the pressure or" the former which would prevent the hi gh pressure consuming units from operating efiiciently will be avoided. 7

It still furtherobject is to provide a mechanism tor the purpose set forth wherein a valve which permits the flow of pressure from a high to a low pressure line is so controlled that the flow is proportional to the demand upon thelow pressure line as long as the pres- Serial No. 54,350.

sure of the high pressure line is above a predetermined point, but wherein the flow is reduced in proportion to a drop in the pressure in the high pressure line below such predetermined point.

These and other objects which will be apparent to those skilled in this particular art are accomplished by means of this invention, one embodiment of which is illustrated in the accompanying drawing which illustrates a preferred arrangement of an apparatus adapted to accomplish the hereinbefore set forth objects.

The mechanism illustrated in shown in connection with two pressure supply lines, one of which ordinarily carries steam or other fluid at high pressure from the high pressure boilers to the high pressure consuming units and the other of which carries steam at low pressure from the low pressure boilers to the low pressure consuming units. A connection between the two lines is provided with a valve by means of which the low pressure line is adapted to be supplied from the high pres sure line so that all pressure consuming units can be supplied from the more economically operated high pressure boilers. Mechanism is provided for opening this valve in proportion to the decrease in pressure of the low pressure line but in order to prevent the low pressure units from being a drain upon the high pressure line and preventing the steam being delivered to the high pressure units at the pressure necessary for eflicient operation, means are provided for closing the valve in proportion to the decrease in pressure of the high pressure line when it falls below a certain'predetermined point, and if such pre sure continues to fall the valve will be closed altogether.

The control system which is illustrated in theaccompanying drawing is shown as applied to a high pressure steam line 1 which is adapted to supply high pressure steam consuming units from modern high pressure boilers (not shown) and it is connected to a low pressure steam line 2 through a connection 3 which is provided with a valve such as the butterfly valve 4 for controlling or cutting off the flow of pressure from the high to low pressure line. I The valve is operated by an arm 5 having a Weight 6 connected to its end in such a manner that the Weight tends to open the valve. The arm 5 is also secured to a cable 7 running over pulleys 8 and c0nnected'to one end of a valve actuating lever 9 which is mounted upon a pivot provided on any suitable support 11.

A pin 12 is secured to the valve actu lever 9 adjacent the opposite end thereof and is received within a slot 13 formed in a connecting link it which extends upwardly from one end of a lever 15 pivoted to a hracket 16 upon the support 11. The opposite end oi? the lever 15 is conn cted by a link 17 to any desired i'orm oi pressure regulator 18 such, for example, as the regulator shown in the patent to l-lopwood No. 1,371,242} granted lvlarch 15, 1921. In the present case the l 17 connects the lever l5 with. the reciprocating cr head 1.9 of the .llopwood regulator and this regulator connected to the hw'n pres no line 1 by a connecting line 19 :ror transmitting the pressrure ot the line 1 to the regulator so as to move the valve actuating lever to close the valve when the pressure in this line tulle below a certain point, as will be hereinafter more fully set forth.

A second pin 2) is mounted in the end Of the lever 9 adjacent the pin l2, and the pin 20 is received within the slot 2l ot a connect-- ing linlr 22 the lower end of which is secured to a lever 23 pivoted in a bracket 24; on the support 11 The opposite end of the lever 23 is connected by a link 25 to the cross head 26 of a second pressure regulator such as the llepwood regulator 27 which is similar in all respects to the high pressure regulator 18 but which is connected to the low pr ssure steam line 2 by a connecting line 27 for transmitting the pressure of the line 2 to the-regulator in such a way that a dec ease in the pressure of this line causes the regulator 27 to move the valve actuating lever 9 so as to open the connecting Salve l.

The high pressure regulator 18 is adjusted in the well known manner so that a decrease of the pressure in the high pressure line 1 with which it associzirtcd below a set predetermined point will cause the cross head 19 to move downwardly. This raises the connecting li'uh lfl; s as to oscillate the valve actuatin lever such a way as to move the valve 4- toward its close ll position. Such movement will be propo 'tional to the decrease in pressure oi? the high pressure line 1 and if such pressure drops sutlieiently the valve l will be closed entirely, thus preventing the low pressure line 2 from draining the line 1 below the pres ire at which the high pressure consuming units operate etliciently. Ordinarily, when the pressure in the line 1 is above predetermined point, the cross head 19 is maintained in its elevated. position so that the end of the slot 13 ot the connecting link isis positioned well below the pin 12, thus permitting the pin 20 to contact with the end of the slot 21 in the connecting link The low pressure regulator 27 is associated with the low pressure line 2 in such a way that when the pressure in the line drops the cross head 26 moves upwardly so that the connecting link 22 is lowered and permitting the valve actuating lever 9 and the valve d to be 1 ed by the Wei-git 6 in such a way as to open the valve l.

it will tin-is be seen that so long as there is sutlicient prr-wssure in the high pressure line to supply the low pressure consuming units without draining pressure away from the high pressure consuming units connected to the line 1 the valve will be open for the passa e of steam pressure from the high pressure line to the low pressure line, and this opening will be proportional to the decrease in presiesure of the low pressure line 2. Should the line 2 talce much pressure from the high pressure line as to prevent the ei'iicient operati of the high 3-ressure consuming units the ml 18 will be actuated so as to close the e 41; in proportion to the drop in pressure e l below this point and if necessary -.i.\'e l viii he closed altogether so as to the hi gh pressure consuming units bean; supplied with steam at the most ellicient operating pressure,

Although I have described this invention in connection with the so off steam pressure it can obviously be applied to any system of fluid pressure.

ll hat l claim as new and desire to secure by Letters Patent is l. "the combination of a high pressure line a low pressure line adapted to be supplied with fluid pressure from said high pressure line, means for regulating the high pressure flow in accordance with the demand upon said low pressure line while the pressure of said high prssure line is maintained above a predetermined point and means for regulating said flow in accordance with the pressure of said high pressure line when its pressure drops below said predetermined point.

2. The combination with a fluid pressure system oi a valve for diverting the flow from said system to a second system, means respousive to the demand of said second system for regulating said valve and means responsive to the pressure of said first system for regulating said valve when said pressure reaches a predetermined minimum.

The combination of a high pressure system, a low pressure system, a valve connect} ring said systems, means resposive to the pressure of said low pressure system for corn tmll'ing said valve so as to diverttiuid pressure to said low t ain said high pressure system when the prc. are ol said low pressure system falls below a predetermined minimum and means responsive to the pressure of said high pressure system for controlling said valve when the pressure of said high pressure system reaches a predetermined minimum.

l. The combination of a high pressure line, a low pressure line, a connection between said lines provided With a valve, means for controlling said valve in response to variations in pressure in said low pressure line so to supply said line with pressure from said high pressure line when required and means responsive to variations in pressure in said high pressure line for controlling said valve when the pressure in said line reaches a predetermined minimum.

5. The combination of a hi gh pressure tem, a low pressure systen'i, a valve adapted to divert fluid pressure from said high to said low pressure system, means responsive to a decrease in the pressure oi? said low pressure system for opening said valve and means responsive to a decrease in the pressure of said high pressure system for controlling said valve.

(5. The combination in a fluid pressure sys-' tem of a high pressure system, a low pressure system, a valve connecting said systems, mechanism responsive to variations in the pressure or said low pressure system for open ing said valve so as to divert pressure to said lovv pressure system from said high pressure s stem and means responsive to variations in the pressure of said high pressure system for rendering said mechanism ineffective.

T. The combination of a high pressure line, a low pressure line, a valve connecting said lines, a lever for opening and closing said val e, means responsive to a decrease in the pressure of said low pressure line for moving said lever so as to open said valve and permit a pressure flow from said high to said low pressure line in proportion to said decrease and means responsive to a decrease in the pressure of said high pressure line for moving said lever so as to close sa d valve in proportion thereto, the connections between said pressure responsive means and said lever being independently operable.

8. The combination of a high pressure line, a low pressure line, a valve connecting said lines, a lever for opening and closing said valve, mechanism provided with a lost mo- I tion connection to said lever and responsive to a decrease in the pressure of said low pressure line for moving saidlever to open said valve and permit a pressure flow from said high to said low pressure line in proportion to saiddecrease, mechanism provided With a lost motion connection to said lever and responsive to a decrease in the pressure of said high pressure line for moving said lever so as to close said valve in proportion thereto, the connections between said mechanisms and said lever being independently operable.

9. The combination of a high pressure line, a low pressure line, a valve connecting said lines, a lever for opening and closing said valve, mechanism having a pin and slot connection to said lever and responsive to variations in the pressure of said low pressure lines for shifting said lever so as to operate said valve to vary the floW from said high to said low pressure line and mechanism having a pin and slot connection to said lever and responsive to a decrease in the pressure of said high pressure line for shifting said lever independently of said first named mechanism so as to close said valve in proportion to said decrease and prevent the draining of said l'iigh by said low pressure line.

10. The combination of a high pressure system, a lOW pressure system, a valve con necting said systems, means responsive to variations in the pressure of said 10W pressure system for operating said valve so as to divert more or less fluid pressure from said high to said low pressure system and means responsive to a predetermined variation in the pressure of said high pressure system for operating said valve.

11. The combination of a high pressure system, a low pressure system, means responsive to variations in the pressure of said low pressure system for diverting fluid pressure from said high to said low pressure system and means responsive to predetermined variations in the pressure of said high pressure system for preventing draining of said high pressure system so as to maintain operating pressure therein.

In testimony whereof, I have hereunto subscribed my name this 31st day of August,

THOMAS A. PEEBLES. 

